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Twisted nematic crystals

A domain-divided twisted nematic crystal cell and method of fabricating thereof. The method of the present invention comprises the steps of providing first and second substrates, forming a photoalignment layer in... [Pg.208]

The first stable commercial liquid crystal display (LCD) device was the twisted nematic (TN) [110], still widely... [Pg.2561]

Schadt M and Flelfrich W 1971 Voltage-dependent optical activity of a twisted nematic liquid crystal Appl. Phys. Lett. 18 127-8... [Pg.2571]

Chiral nematic Hquid crystals are sometimes referred to as spontaneously twisted nematics, and hence a special case of the nematic phase. The essential requirement for the chiral nematic stmcture is a chiral center that acts to bias the director of the Hquid crystal with a spontaneous cumulative twist. An ordinary nematic Hquid crystal can be converted into a chiral nematic by adding an optically active compound (4). In many cases the inverse of the pitch is directiy proportional to the molar concentration of the optically active compound. Racemic mixtures (1 1 mixtures of both isomers) of optically active mesogens form nematic rather than chiral nematic phases. Because of their twist encumbrance, chiral nematic Hquid crystals generally are more viscous than nematics (6). [Pg.193]

Thermotropic cholesterics have several practical applications, some of which are very widespread. Most of the liquid crystal displays produced use either the twisted nematic (see Figure 7.3) or the supertwisted nematic electrooptical effects.6 The liquid crystal materials used in these cells contain a chiral component (effectively a cholesteric phase) which determines the twisting direction. Cholesteric LCs can also be used for storage displays utilizing the dynamic scattering mode.7 Short-pitch cholesterics with temperature-dependent selective reflection in the visible region show different colors at different temperatures and are used for popular digital thermometers.8... [Pg.428]

Figure 8.11 Illustration of Mauguin twisted nematic cell, reported in 1911. Substrates are thin mica plates, which are uniaxial with their optic axis parallel to plane of plates. Apparently, uniaxial crystal stmcture of mica produces strong azimuthal anchoring of nematic LCs of Lehmann, such that director is parallel (or perpendicular) to optic axis of mica sheets at both surfaces. Mauguin showed that method of Poincard could be used to explain optics of system if it was assumed that LC sample created layer of material with uniformly rotating optic axis in twisted cells. Figure 8.11 Illustration of Mauguin twisted nematic cell, reported in 1911. Substrates are thin mica plates, which are uniaxial with their optic axis parallel to plane of plates. Apparently, uniaxial crystal stmcture of mica produces strong azimuthal anchoring of nematic LCs of Lehmann, such that director is parallel (or perpendicular) to optic axis of mica sheets at both surfaces. Mauguin showed that method of Poincard could be used to explain optics of system if it was assumed that LC sample created layer of material with uniformly rotating optic axis in twisted cells.
A physicist would say the liquid crystal adopted a twisted nematic structure. [Pg.41]

Supertwisted nematic display, 15 114 Super twisted nematic liquid crystal display (STN-LCD), 9 340 Super ultra-low emissions vehicle (SULEV), 13 855... [Pg.909]

Twisted nematic liquid crystal sandwiched between two glass plates, with the director aligned parallel to the plates, with one of the plates turned in its own plane about an axis normal to it. [Pg.133]

Colour Displays from Twisted Nematic Liquid Crystals... [Pg.310]

Afterwards there appeared what has become the main application liquid crystal displays (LCDs) based on the twisted nematic (TN) mode. These are commonly used for flat panel displays (e.g., desk calculators). Thin film transistor (TFT) LCDs enabled a large number of segments (e.g., 640 x 1024) to be used and they had advantages like... [Pg.407]

Several exciting phenomena described for non-chiral nematic systems were also reported for nanoparticle-doped chiral nematic liquid crystals. We mentioned the work of Kobayashi et al., who, most notably, demonstrated a frequency modulation twisted nematic (FM-TN) mode and fast switching characteristics using metal nanoparticles as dopants [301-307, 313, 314],... [Pg.358]

Liquid crystals can display different degrees of long-range order, dependent on temperature, chemical composition, and the presence or absence of electric fields. In the nematic phase, the molecular axes point in a common direction, denoted by the director n but the molecular centers are otherwise arranged randomly. Because of the low degree of long-range order, nematic LCs have viscosities typical of ordinary liquids, and displays based on nematic LCs can operate at television frame rates. The most popular nematic-based display, the twisted nematic (TN), will be discussed in more detail below. [Pg.116]

Super-twisted nematic liquid crystal displays (STN-LCDs) 45000000... [Pg.1]

The twisted nematic liquid crystal display (TN-LCD) was reported by Schadt and Helfrich of F. Hoffman-La Roche in Basle, Switzerland in 1970. This was part of a tripartite collaboration between F. Hoffman-La Roche in Basle, Brown Boveri of Baden and Ebauche in Neuchatel, all in Switzerland. The intention was to design and develop flat panel displays, e.g. for digital watches. The first LCD factory was constructed in Lenzburg, Switzerland in the mid-1970s by Videlec, a subsidiary of Brown Boveri. Since then the TN-LCD has... [Pg.60]

Figure 3.7 Schematic representation of a twisted nematic liquid crystal display (TN-LCD). ... Figure 3.7 Schematic representation of a twisted nematic liquid crystal display (TN-LCD). ...
Gooch and Tarry plot of transmission versus the coefficient, u, and the corresponding birefringence values, An, for a Twisted Nematic Liquid Crystal Display TN-LCD of thickness 6.55 pm operating between parallel polari-... [Pg.63]

See other pages where Twisted nematic crystals is mentioned: [Pg.275]    [Pg.275]    [Pg.2562]    [Pg.192]    [Pg.203]    [Pg.203]    [Pg.203]    [Pg.338]    [Pg.339]    [Pg.14]    [Pg.71]    [Pg.382]    [Pg.428]    [Pg.188]    [Pg.307]    [Pg.116]    [Pg.672]    [Pg.211]    [Pg.91]    [Pg.937]    [Pg.2352]    [Pg.461]    [Pg.462]    [Pg.354]    [Pg.882]    [Pg.45]    [Pg.47]    [Pg.155]    [Pg.197]    [Pg.79]    [Pg.98]   
See also in sourсe #XX -- [ Pg.47 ]



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